The free function slaughter continues. The newest release guts the remainder of the free functions, moving nearly everything possible into a protocol extension. Left alone, abs() whistles pointedly, refusing to make eye contact with SignedNumberType or AbsoluteValuable. Its days are numbered.

The Lazy* group of types and protocols have been updated significantly, with clearer naming and official protocols for LazySequenceType and LazyCollectionType.

MutableSlice, MutableIndexable, and ReverseIndexType all join the family to support new mutable collection slicing capabilities. Welcome, everyone!

Many methods that take closures, like map, filter, and contains, are now marked as rethrows, so they can accept throwing closures and pass on any thrown errors.